Ryan said he'll campaign instead for GOP congressional candidates.
The Wisconsin Republican is holding a conference call with GOP lawmakers.
Republicans, who now enjoy a majority in both the House of Representatives and the Senate, are afraid of losing their dominance in Congress in the upcoming elections due to the possible negative effect of the outspoken and controversial billionaire presidential candidate. But a spokesperson for Senator Johnson's campaign told 27 News he had no comment on whether Johnson still supports Trump or will vote for him.
Ryan is also telling congressional Republicans he won't defend Donald Trump now or in the future and will spend the next month defending his party's House majority. One member, two sources on call said, pointedly told Ryan that the better Trump does in November, the better the House GOP will do.
The call comes three days after The Washington Post released a video of Trump from 2005 making lewd remarks about women and asserting he can get away with grabbing their genitals and other actions because he's a celebrity.
While neither Ryan nor McConnell immediately withdrew formal support for Trump, Republican leaders in Washington held anguished discussions throughout the evening about how the party should proceed with a badly wounded and potentially toxic nominee.
But the source on the call appeared to suggest Ryan had effectively conceded the election to Trump's Democratic rival Hillary Clinton, who is leading in national polls and in several key battleground states.
Ryan did not mention Trump by name at the rally but said, "it is a troubling situation". The Trump campaign then said that running mate Mike Pence would attend, but that too was canceled.
Wofford cites Trump's support for the Second Amendment, his opposition to free trade deals like the Trans Pacific Partnership, and his pledge to secure the country's borders as issues where she agrees.
Appearing on "This Week" on ABC-TV on Sunday, U.S. Rep. Charlie Dent, R-Pa., reiterated his insistence that GOP leaders dump Trump and find someone else to run in his place.
Asked about the video in the debate, Mr Trump turned his fire on Mrs Clinton's husband, ex-President Bill Clinton, whom he described as "abusive to women".
But on the call Monday, the message was unequivocal: Trump will no longer enjoy whatever political firepower Ryan could bring to the presidential race in its final stretch.
And while scores of Republicans have rebuked their party's nominee, some of the most prominent ones have stopped short of calling for him to exit the race. "I'm out. I can no longer in good conscience endorse this person for president", he said in a statement.
Trump's campaign was already struggling before the new video was released, due in part to his uneven performance in the first presidential debate.